1. Technical Field
The present invention relates to an image display device and a head mounted image display device.
2. Related Art
Hitherto, head mounted displays (HMD) mounted on the head of an observer have been known as image display devices that display an image (for example, see JP-A-2008-99222).
The HMD disclosed in JP-A-2008-99222 includes a video display device that displays a video so as to be capable of being visually recognized by an observer as a virtual image, an eyepiece optical system, and a supporting unit. Among these, the eyepiece optical system guides video light emitted from the video display device to an observer's eyes, and the supporting unit supports the eyepiece optical system in front of the eyes of the observer and is equivalent to a frame of spectacles.
In addition, the video display device includes a light source constituted by a light emitting diode (LED), a heat absorbing member, a flexible printed circuit (FPC), and a housing that accommodates the above-mentioned components therein.
Among these, the light source is fixed to a land portion of the FPC by soldering. The heat absorbing member is fixed to a surface on a side opposite to a mounting surface of the light source in the FPC by solder. In addition, a shielding wire is connected to the heat absorbing member, and the shielding wire is exposed to the outside of the housing. Thereby, heat generated by the light source is absorbed into the heat absorbing member, is guided to the outside of the housing through the shielding wire, and is radiated. That is, in the HMD disclosed in JP-A-2008-99222, the shielding wire is used as a heat conduction member.
However, in the HMD disclosed in JP-A-2008-99222, the shielding wire transmits the heat absorbed by the heat absorbing member to the outside of the housing. For this reason, there is a tendency for the contact area between the shielding member and the heat absorbing member to be reduced, and thus the heat conduction efficiency of the shielding member is low, which results in a problem in that it is not possible to radiate heat from the light source with a good efficiency. In addition, in a configuration of the HMD, there is the possibility of a light source or a liquid crystal panel being shifted due to the stress of the shielding wire, and furthermore, there is a problem in that an image formed by the light source and the liquid crystal panel and projected may be shifted.
As described above, when heat generated by the light source is not able to be radiated with a good efficiency, there is an increased possibility that heat is transmitted to a lateral side on the observer side in the housing. In this manner, when the temperature of the lateral side on the observer side increases, the observer feels heat, which results in a problem of deterioration in the feeling of wearing.